Process for the ionogenic polymerization of omega-lactams with oxy- or thioalkynes as activators



United States Patent 3,379,697 PROCESS FOR THE IONOGENIC POLYMERIZA- TION 0F w-LACTAMS WITH OXY- 0R THEO- ALKYNES AS ACTIVATORS Johannes van Mourik, Geleen, and Johannes van Beveren, Sittard, Netherlands, assignors to Stamicarbon N.V., Heerlen, Netherlands N0 Drawing. Filed Feb. 24, 1965, Ser. No. 435,035 Claims priority, application Netherlands, Feb. 28, 1964, 64-1,963 16 Claims. (Cl. 260-78) ABSTRACT OF THE DISCLOSURE The use of compounds of the formula:

RCE'C-XR' wherein R is the hydrogen atom, an alkyl hydrocarbon group of up to about 8 carbon atoms, or an aryl hydrocarbon radical having 1 or 2 benzenoid rings, and R represents an alkyl hydrocarbon group of up to about 8 carbon atoms or an aryl hydrocarbon radical having from 1 to 2 benzenoid rings, and X represents an oxygen or a sulphur atom, as promoters in the ionogenic or anionic polymerization of lactams, is disclosed.

The present invention relates to the ionogenic or anionic polymerization of lactams.

Prior to this invention it has been common knowledge that various lactams may be subject to ionogenic or anionic polymerization, usually carried out with an alkali-metal compound as a catalyst, to form useful polymer products. It has also been known that such process was considerably accelerated by also adding a promoter to the polymerization mixtures. The known promoters used to this end have generally been nitrogen compounds, such as isocyanates, carbodiimides, cyanamides, and, in general, compounds with a tertiary nitrogen atom bound to carbonyl, thiocarbonyl, sulphonyl, or nitroso groups. By the addition of these promoters the polymerization reaction could be carried out in a short period of time and at temperatures lower than the melting point of the polymer. Thus, from lactam monomers, the molecule of which contains at least 6 carbon atoms in its ring, a solid product can be directly obtained in the shape of the reaction vessel or container in which the polymerization has been carried out.

It has now been discovered and found that good results in such polymerization reactions are obtained through the use of a non-nitrogen compound as a promoter.

The present invention provides as novel and effective promoters for the aforesaid ionogenic polymerizations, compounds having the formula:

(where R and R are the same or different hydrocarbon groups or R is hydrogen, while X denotes an oxygen or a sulphur atom). Examples of suitable promoters according to the invention are: l-octyloxy-l-butyne, l-ethoxy lheptyne, pentoxy-ethyne, phenoxy-ethyne, naphthoxyethyne, isopropoxy-ethyne, l-butoxy-l-butyne, l-methoxyl-butyne, l-methoxy-l-propyne, methox-y-ethyne, methylthio-ethene, -1-pentylthio-l-butyne, l-ethylthio-l-propyne, l-propylthio-l-pentyne.

In general, R represents a hydrogen atom, an alkyl hydrocarbon group of up to about 8 carbon atoms or an aryl hydrocarbon radical having from one or two benzenoid rings and R represents an alkyl hydrocarbon group of up to about 8 carbon atoms or an aryl hydrocarbon radical having from 1 or 2 benzenoid rings.

In general it appears that either the ether compounds "ice or the sulphur compounds with the aforesaid structure may be used as promoter.

In the ionogenic or anionic catalytic polymerization of lactams the promoter is used in combination with a catalyst. The well-known catalysts for this polymerization are, for instance: lactam-metal compounds containing a metal atom bound to the nitrogen atom, such as sodium caprolactam, and substances from which, by reaction with lactam, such lactam-metal compounds are formed, for instance, triisopropyl aluminum, diethyl zinc, and alkalimetal alkyls, further alkali metals, alkali-earth metals, and compounds of these metals showing an alkaline reaction, such as hydrides, oxides, hydroxides, and carbonates, and also Grignard compounds, such as alkyl magnesium bromide and aryl magnesium bromide. The particular catalyst used forms no part of this invention. To the contrary, it is a feature of this invention that its advantages may be achieved using any of the conventional known catalysts employed in the ionogenic polymerization of lactams.

The amount of catalyst used may be varied within wide limits. Usually use is made of 0.1-3 mol. percent with respect to the amount of monomer to be polymerized, but also larger amounts, e.g. 5-10 mol. percent, may be used. In general, an amount between 0.1 and 10 mole percent of the catalyst will be used, based on the amount of monomer to be polymerized, and preferably the amount of catalyst is at most about '3 mole percent.

The amount of promoter to be used in the practice of this invention may also be varied. However, when large amounts of promoter are used, e.g. more than '10 mol. percent, a lower degree of polymerization is obtained than when smaller amounts are used. Accordingly, use of about 0.05-2 mol. percent of promoter, with respect to the lactam, in the present range of practice of this invention employed for optimum polymerization. In general, about 0.05-10 mole percent of the promoter, with respect to the lactam monomer being polymerized, may !be used.

In carrying out the process of this invention, the lactam monomer may be mixed with the catalyst and the promoter in any simple way. By preference, the lactam is first melted, the catalyst is distributed in the melt, and the mixture is heated to the polymerization temperature, after which the promoter is added with stirring.

The temperature at which the polymerization is carried out may be in the same temperature range of about 250 C. that is commonly used for the ionogenic polymerization of lactams. Use is preferably made of an initial temperature of about 90-150 (2., while, owing to the exothermic polymerization reaction, the temperature may rise during the reaction, but usually remains below about 200215 C. At these temperatures the polymerization is generally completed within an hour, often within half an hour.

As a particular embodiment of the invention, use is made of a temperature lying between the melting point of the lactam monomer and that of the polymer to be obtained, whereby solid macromolecular end products are obtained in the polymerization as shaped products the dimensions of which correspond to those of the reaction vessel or chamber in which the polymerization has been carried out.

The polymerization may be conducted with various omega lactams, such as butyrolactam, caprolactam, oenantholactam, caprylolactam, decyllactam, undecyllactam, or laurinolactam. Mixtures of two, three, or more such lactams may also be copolymerized. If mixtures are copolymerized, copolyamides are obtained, e.g. oenanth0 lactam-caprolactam-laurinolactam copolyamide, laurinolactam-oenatholactam copolyamide, undecyllactam-caprolactam copolyamide, caprolactam-caprylolactam-laurinolactam copolyamide, laurinolactam-caprolactam copolya-mide, butyrolactam-caprolactam copolyamide or the like. The structure and the resulting properties of the copolyamides can, of course, be influenced and varied by the composition of the starting mixture of monomers.

The process according to the invention may furthermore be used for the manufacture of dyed or colored products. To this end one or more substances which influence the outward appearance and/ or the properties of the polymerization product can be mixed with the starting material in a simple way. For instance, dyestuffs and/ or all kinds of fillers, such as wood flour, Carborundum, carbon black, powdered shale, coal dust, and coke dust, may be distributed in the lactam melt. Natural and/or synthetic fibres, threads and/ or fabrics made thereof may also be processed into the lactam melt. Furthermore, macromolecular products, e.g. polystyrene, polyformaldehyde, polypropylene, polyethylene, and polyamide, and also polycondensation products of aldehydes with phenol, melamine and/or urea may be added to the lactam melt, so that macromolecular products with special properties can be obtained.

The principles and practice of the invention will be further understood by reference to the following examples:

Examples 1-10 The polymerization is carried out in a glass cylinder (diameter 2.5 cm.), in which bars are made. The cylinder is put in an oil bath the temperature of which is controlled.

- In these experiments a molten mixture of 30 grams of e-caprolactam and 0.6 gram of sodium-caprolactam is brought into the cylinder, while a flow of nitrogen is passed through the liquid by means of an inlet tube.

Subsequently, the promoter is added and after 30 seconds the flow of nitrogen is stopped and the inlet tube removed. After completion of the polymerization the shaped bar is taken from the cylinder.

The table mentions the amount of promoter (mol. percent), the temperature of the oil bath, and the polymerization t1me.

Promoter, Tcmpera- Time, No. Promoter mol. ature, 0. min.

' Percent 1 l-octoyloxy-l-butyne 0.6 150 9 2 do 0. 6 120 20 3 l-ethoxy-l heptyne 0. 6 150 9 4 do 0. 6 120 10 5- do 0. 6 90 20 6. Pentoxyethyne 0. 6 150 11 7 o 0.6 120 9 8 Phenoxy-ethyue 0.6 150 3500 9 l-propylthio-l-pentyne 0.6 150 200 10 l-methoxy-l-hexyne 0. 6 150 6 It will be understood this invention may be practiced in modes other than those specifically illustrated herein and, accordingly, is limited only by the spirit and scope of the following claims.

What is claimed is:

1. In the process for the anionic polymerization of omega lactams in the presence of an anionic polymerization catalyst, the improvement which consists essentially in the added presence of a compound, as a promoter, having the formula RC C-X--R' wherein R represents a member selected from the class consisting of a hydrogen atom, alkyl hydrocarbon radicals having up to about 8 carbon atoms and aryl hydrocarbon radicals having from 1 to 2 benzenoid rings and R represents a member selected from the class consisting of alkyl hydrocarbon radicals having up to about 8 carbon atoms and aryl hydrocarbon radicals having from 1 to 2 benzenoid rings, and X is an oxygen atom or a sulphur atom.

2. The process according to claim 1, wherein said polymerization is carried out at a temperature between the melting point of the lactam monomer and the melting point of the polymerization product.

3. The process of claim 1 wherein said lactam is ecaprolactam.

The process of claim 1 wherein said promoter is 1- octyloxy-l-butyne.

5. The process of claim 1 wherein said promoter is 1- ethoxy-l-heptyne.

6. The process of claim 1 wherein said promoter is pentoxy-ethyne.

7. The process of claim 1 wherein said promoter is l-propylthio-l-pentyne.

8. The process of claim 1 wherein said promoter is lmethoxy-l-hexyne.

9. The process of claim 1 wherein said promoter is added in an amount of from about 0.05-10 mol. percent with respect to the lactam monomer being polymerized.

It). The process of claim 9 wherein the amount of said promoter is at most about 2 mol. percent.

11. The process of claim 1 wherein a mixture of lactam monomers is employed to produce a copolymer.

12. The process of claim 1 wherein said lactam monomer is selected from the class consisting of butyrolactam, caprolactam, oenantholactam, caprylolactam, decyllactam, undecyllactam and laurinolactam.

13. The process of claim 1 wherein the polymerization is conducted in the temperature range of from about to 250 C.

14. The process of claim 13 wherein said temperature is initially maintained in the range of from about 90 to C.

15. The process of claim 1 wherein said catalyst is present in an amount between about 0.1 and 10 mol. percent.

16. The process of claim 15 wherein the amount of said catalyst is at most about 3 mol. percent.

References Cited UNITED STATES PATENTS 3,234,152 2/1966 Fuller 260-78 WILLIAM H. SHORT, Primary Examiner.

H. ANDERSON, Assistant Examiner. 

